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991.
丙烯酸酯无皂乳液的研究 总被引:4,自引:1,他引:4
在甲基丙烯酸甲酯和丙烯酸丁酯的无皂乳液体系中,加入适量的自制聚氨酯型反应性乳化剂(URE),考察单体配比和有机溶剂对乳胶膜性能的影响,并研究了聚合物乳液的稳定性。结果表明:与传统乳液聚合体系相比,所合成的胶乳耐电解质、耐酸碱、耐有机溶剂的性能均好。 相似文献
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Wen Tan Horacio J. Marquez Tongwen Chen Jizhen Liu 《Computers & Chemical Engineering》2004,28(12):2667-2675
Multimodel analysis and controller design for nonlinear processes via gap metric is discussed. It is shown that the loop-shaping H∞ approach can integrate the procedure of selecting operating points and the local controller design. The local controllers can guarantee not only stability but also performance specified by the pre- and/or post-compensators. Thus, at each operating points, local controllers can have similar performance, and the global performance of the system can be predicted. 相似文献
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《Journal of Great Lakes research》2022,48(6):1329-1336
Climate-driven disturbances threaten the sustainability of coastal communities in the Great Lakes Basin. Because such disturbances are unpredictable, their magnitude, number and intensity are changing, and they occur at varying temporal and spatial scales. Consequently, communities struggle to respond in effective ways. The expected intensification of climate-driven disturbances will require that community capacity and governance structures match the spatial and temporal scales of these disturbances, as the most sustainable social and economic systems will be those that can respond at similar frequencies to key natural system drivers. The Climate Governance Variability in the Great Lakes Research Coordination Network (CGVG-RCN) was recently established to address questions about the relationship between climate-driven disturbances and community response. The objective of this short communication is to introduce the ideas behind the CGVG-RCN, outline its goals, and facilitate engagements and collaboration with social and natural scientists interested in social-ecological systems in the Great Lakes Basin. 相似文献
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Electropolymerization of pyrrole on lead substrate electrode was studied. Due to electrochemical activity of Pb in acidic media, this process is only possible at basic pHs. For this purpose, electropolymerization process was performed in an aqueous solution of Na2SO4 with pH 12. Potentiodynamic cycling shows the Pb oxidation at the first cycles. In subsequent cycles, polypyrrole film grows on the oxidized lead substrate. Of course, as the passive film is highly porous, a composite of polypyrrole/PbSO4 is formed in the first layers. However, subsequent cycling leads to the formation of pure polypyrrole film. According to this structure and strong connection of the polymer film to the substrate surface via this composite layer, the polypyrrole film deposited on the lead surface has enhanced mechanical stability. AFM measurements showed peculiar smoothness of both composite and lateral polypyrrole films. This synthesis approach is of particular interest for the preparation of highly stable polymer films and fabrication of supercapacitors with a polymer/PbSO4 conductive structure. 相似文献
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Linear low‐density polyethylene (LLDPE), based on butene‐1 or hexene‐1, was irradiated with γ‐rays under vacuum or in the presence of air. The study focused on the influence of the dose rate and the γ‐dose on the thermal properties of LLDPE. Differential scanning calorimetry, thermogravimetric analysis (TGA), and TGA/FTIR techniques were used to address the thermal behavior as a result of γ‐irradiation. During this irradiation, competition between crosslinking and scission reactions, subsequent to oxidation reactions, occurred in the polymeric material, which strongly depends on the experimental conditions. A decrease of the crystallinity for γ‐irradiated samples was observed in particular for samples irradiated under vacuum. This observation may be explained by increased hindrance of segment mobility due to crosslinking reactions that prevent crystal growth. TGA investigations revealed an enhancement of the thermal stability for samples irradiated under vacuum but not for those irradiated in air. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2790–2795, 2006 相似文献
1000.
以氧化镁和氧化锌为主稳定剂的PVC的热稳定性和力学性能 总被引:3,自引:0,他引:3
用HAAKE流变仪研究了氧化镁/氧化锌稳定体系对聚氯乙烯的动态热稳定性能。结果发现,在氧化镁/氧化锌质量比为2/3的条件下,配合环氧大豆油、硬脂酸钙、无毒亚磷酸酯和有机稳定剂作为辅助稳定剂,其初期着色和热稳定效果都超过了市售钙锌稳定体系,流变性能和动态热稳定特性接近铅盐稳定体系。用这种稳定体系稳定的PVC的力学性能与市售钙锌稳定体系稳定的相当。 相似文献